IRedMail (postfix) not sending mail?

Question

Debian

Mail comes to the server, but it does not teach anywhere to write.
the server is on nat, port 25 tcp will be forwarded to it. There are mx records in dns.
When I try to send a letter (via the web interface) to gmail, the log says:

Apr  2 18:21:49 mail postfix/smtp[3093]: connect to gmail-smtp-in.l.google.com[173.194.71.26]:25: Connection timed out
Apr  2 18:21:49 mail postfix/smtp[3092]: connect to gmail-smtp-in.l.google.com[173.194.71.26]:25: Connection timed out
Apr  2 18:21:49 mail postfix/smtp[3094]: connect to gmail-smtp-in.l.google.com[173.194.71.26]:25: Connection timed out
Apr  2 18:22:10 mail postfix/smtp[3092]: connect to alt1.gmail-smtp-in.l.google.com[173.194.64.26]:25: Connection timed out
Apr  2 18:22:10 mail postfix/smtp[3093]: connect to alt1.gmail-smtp-in.l.google.com[173.194.64.26]:25: Connection timed out
Apr  2 18:22:10 mail postfix/smtp[3094]: connect to alt1.gmail-smtp-in.l.google.com[173.194.64.26]:25: Connection timed out
Apr  2 18:22:31 mail postfix/smtp[3092]: connect to alt2.gmail-smtp-in.l.google.com[74.125.133.26]:25: Connection timed out
Apr  2 18:22:31 mail postfix/smtp[3093]: connect to alt2.gmail-smtp-in.l.google.com[74.125.133.26]:25: Connection timed out
Apr  2 18:22:31 mail postfix/smtp[3094]: connect to alt2.gmail-smtp-in.l.google.com[74.125.133.26]:25: Connection timed out
Apr  2 18:22:52 mail postfix/smtp[3092]: connect to alt3.gmail-smtp-in.l.google.com[74.125.130.26]:25: Connection timed out
Apr  2 18:22:52 mail postfix/smtp[3093]: connect to alt3.gmail-smtp-in.l.google.com[74.125.130.26]:25: Connection timed out
Apr  2 18:22:52 mail postfix/smtp[3094]: connect to alt3.gmail-smtp-in.l.google.com[74.125.130.26]:25: Connection timed out
Apr  2 18:23:13 mail postfix/smtp[3092]: connect to alt4.gmail-smtp-in.l.google.com[173.194.76.26]:25: Connection timed out
Apr  2 18:23:13 mail postfix/smtp[3094]: connect to alt4.gmail-smtp-in.l.google.com[173.194.76.26]:25: Connection timed out
Apr  2 18:23:13 mail postfix/smtp[3093]: connect to alt4.gmail-smtp-in.l.google.com[173.194.76.26]:25: Connection timed out

173.194.71.26 is pinged.
The server was installed on an empty debian 6 as written here .

Answer 1

Well, it is logical that port 25 is closed on the firewall either on the Debian itself, or on the router, or at the provider.
Just test telnet ip 25
Open the port and you will be happy.

Answer 2

see if you are blacklisted on the Internet, for example here mxtoolbox.com/blacklists.aspx
In general, the smtpl server can ignore you, this is due to different policies of the host company, for example, workload, antispam
Your mailer in this case should put the letter on resend at some interval to poll for availability and send if successful.

Answer 3

Try to connect from the server telnet 74.125.130.26 25 - if the letters are not visible, then there is a problem with the network / firewall - then you need to dig somewhere else.

Answer 4

By the way, if the beeline is for individuals, then in your personal account, by default, outgoing port 25 is closed. But in any case, telnet to the blurry servers and write back about the result